The present invention relates to a grenade cartridge adapted to be fired from a firing tube, and more specifically the invention relates to a reusable cartridge designed to be reloaded for firing different kinds of projectiles, such as explosive shells and practice ammunition.
The grenade cartridge as herein referred to is conceived primarily to be fired from a hand held firing tube having a firing mechanism. As an alternative, firing may be done from a detachable firing tube that is supported on a small caliber rifle. The cartridge of this invention is however not exclusively used with firing tubes of this kind, but may be adapted and used for firing also from firing tubes of other larger or smaller caliber and from weapons with automatic reloading capacity.
An explosive grenade is a projectile of considerable weight, typically having a caliber of 40 mm, and would generate a powerful recoil at high firing velocities. For that reason, the grenade cartridge often is structured to ensure uniform gas pressures and muzzle velocities also at lower firing velocities. Through these measures, firing of that comparatively heavy projectile may be done at a reduced recoil effect. Typically, the cartridges are formed to have a first chamber or high-pressure chamber, from which the explosive gases reach a second chamber or low-pressure chamber. The structure as such is known as a high-/low pressure system.
A problem connected with training practice for this type of hand held grenade weapons is the high financial cost for the training ammunition. The comparatively low firing velocity drives the projectile into a typical ballistic trajectory, which is characterized by a slight side drift caused from the rotation about the longitudinal axis of the projectile. Evidently, there is a desire to provide a training ammunition that performs closely to the ballistic characteristics of the sharp grenade in order to properly prepare the personnel for their tasks. Therefore, the training ammunition should have a weight and firing properties that correspond with those of the sharp grenade. Shooting practice with disposable grenade cartridges however leads to considerable costs caused by the structural measures taken in the sharp grenade cartridge.
A conventional alternative for training with full caliber ammunition involves an insert barrel that is inserted in the bore of the weapon and adapted for firing 9 mm tracking ammunition, e.g. Naturally, a bullet like that would substantially depart from the weight, flight properties and recoil of the sharp grenade. For that reason, this alternative is often considered not to offer sufficient training on the weapon. Accordingly there is a desire for a serviceable and reusable training grenade cartridge for shooting practice on this kind of grenade weapons.
In a reusable grenade cartridge adapting the principle of a high-/low pressure system, a separate propellant cartridge is inserted into a cartridge chamber of the high-pressure chamber, through an opening in the end plane of the grenade cartridge. A problem connected therewith is the reactive force that tends to separate the propellant cartridge from the grenade by pressing the propellant cartridge out of the cartridge chamber.
In a reusable grenade cartridge adapting the principle of an insert barrel for shooting practice, a separate cartridge with projectile is inserted in a cartridge chamber that opens in the end plane of the grenade cartridge. A problem connected with this solution is the resistance from the rifled bore on the accelerated projectile that tends to pull the grenade cartridge in the firing direction.
Above said drawbacks lead to the risks of deformation forces generated to act between the grenade cartridge and the after most rim of the firing tube, against which the cartridge is supported by means of an outwardly projecting, radial flange.
The object of the present invention is to provide a reusable grenade cartridge wherein the above stated problems and drawbacks are removed.
Another object is to provide a shooting practice ammunition having similar characteristics as that of an explosive grenade cartridge, and at a substantially lower expense per fired round due to the reloading capacity and repetitive use of the cartridge.
These objects are met in a grenade cartridge as defined by the characterizing part of claim 1. Advantageous embodiments of the invention are defined in the subclaims.
Briefly, the invention suggests a rechargeable grenade cartridge adapted to be fired from a firing tube. The grenade cartridge comprises a projectile, a cartridge and a propellant cartridge with primer. In a preferred embodiment the grenade cartridge is a two-part element, a front portion of which is tube shaped and formed in a first end to accommodate the projectile in the firing direction. A second end of the front portion of the cartridge is releasably retained in assembled relation with a rear portion of the two-part cartridge, and a separate and exchangeable propellant or propellant cartridge is axially and radially supported by the front and rear portions of the cartridge when assembled.
In another preferred embodiment the rear portion of the cartridge forms an end plane and the front portion comprises a high-pressure chamber axially extending in the center of the front cartridge portion, the high-pressure chamber radially enclosing the propellant cartridge in the assembled relation of the two cartridge portions. The propellant cartridge is axially supported between a front end-wall of the high-pressure chamber and the end plane such that the propellant cartridge protrudes, with a radially undercut portion thereof, through a central opening in the end plane.
In an alternative embodiment the end plane of the grenade cartridge is formed to support a firing pin for a separate propellant cartridge arranged to be inserted in a cartridge chamber, formed in the high-pressure chamber.
In yet another embodiment, the rear cartridge portion is ring-shaped, and the front cartridge portion projects with an end-plane thereof through a central opening of the annular rear cartridge portion. A separate propellant cartridge is receivable in a cartridge chamber such as to extend in level with the end-plane, and heels are supported in the end-plane of the front portion for a spring biased engagement with an extractor flange that is formed on the propellant cartridge.
A common feature of these and other embodiments is that reactive forces, generated upon firing and acting between the propellant cartridge and the grenade cartridge or the high-pressure chamber, are completely absorbed by the grenade cartridge. The reactive force is thus prevented from generating a separation of the propellant cartridge from the grenade cartridge. This way, the reactive force is directed towards the shock-absorbing bottom of the firing mechanism, such that deforming forces that would otherwise appear between the grenade cartridge and the firing tube may be successfully prevented.